Silo unloader structure



Dec. 14, 1965 F. E. BUSCHBOM 3, 3,2 6

SILO UNLOADER SIRUCTURE Filed Dec. 24, 1958 8 Sheets-Sheet 1 INVENTOR. F2 0m 5. BUSCHBOM FIG. 1

Dec. 14, 1965 F. E. BUSCHBOM 3,223,256

SILO UNLOADER STRUCTURE Filed Dec. 24, 1958 8 Sheets-Sheet 2 ATToRNEKs- Dec. 14, 1965 F. E. BUSCHBOM SILO UNLOADER STRUCTURE 8 Sheets-Sheet 5 Filed Dec. 24, 1958 0 uh rl l l U IN VE NTOR. Fwm E. BUSCHBOM B %w ZUM M Arromvsvs Dec. 14, 1965 F. E. BUSCHBOM 3,223,255

SILO UNLOADER STRUCTURE Filed Dec. 24, 1958 8 Sheets-Sheet 4 INVENTOR.

H6. 5 FLomEBz/smaom W- QUMW ATToRNE. Ks

Dec. 14, 1965 F45. BUSCHBOM 3,223,256

SILO UNLOADER STRUCTURE Filed Dec. 24, 1958 8 Sheets-Sheet 5v 1N VENTOR. Home E. BUJTHBOM ATT-ORNEYJ Dec. 14, 1965 F. E. BUSCHBOM SILO UNLOADER STRUCTURE 8 Sheets-Sheet 6 Filed Dec. 24, 1958 X A 7 A 0 m 0 H W+ I m/ 7 H 1 A7 90 21 m M Mm R s 08 N TH NC R W m 8 T E A Dec. 14, 1965 F. E. BUSCHBOM SILO UNLOADER STRUCTURE 8 Sheets-Sheet '7 Filed. Dec. 24, 1958 IN VENTOR. Fzarof. BIAS'CHBOM ArroRm-zw' Dec. 14, 1965 F. E. BUSCHBOM 3, 6

S ILO UNLOADER STRUCTURE Filed Dec. 24, 1958 8 Sheets-Sheet 8 IN VENTOR. FZorof. Buscuaom A r-roxwsm- United States Patent 3,223,256 SILO UNLOADER STRUCTURE Floyd I3. Buschbom, Albert Lea, Minn., assignor to Vandaie Corporation, Long Lake, Mind, a corporation of Minnesota Filed Dec. 24, 1958, Ser. No. 782,756 16 Claims. (Cl. 214-17) This invention relates to new and useful improvements in silo unloader structure of the type shown in Patent 2,794,560 and in co-pending applications Serial No. 732,735 filed May 2, 1958, now Patent 3,017,043 and Serial No. 452,826, filed August 30, 1954, now Patent 2,794,272.

More specifically, this invention relates to new and useful improvements in supporting, control and driving structure for silo unioaders.

It is an object of this invention to provide new and usefui supporting structure for a silo unloader in which the unloader is substantially supported upon the surface of ensilage upon extending helical flight means and outrigger members.

It is a further object of this invention to provide a silo unloader supporting structure in which there is provided three point support for the unloader on the surface of the ensilage.

It is still a further object of this invention to provide a silo unloader supporting structure in which substantial support for the unloa-der is provided by a plurality of drive members.

It is a further object of this invention to provide a new and useful driving and supporting structure extending in prolongation substantially at right angles to an elongated conveying means.

Still a further object of this invention resides in the provision of new and useful driving and supporting structure for a silo unloader including opposed outrigger driving members, and wall engaging means positioned in cooperation therewith.

Stiil a further object of this invention is to provide a new and useful differential drive structure for silo unloaders.

Still a further object of this invention is to provide new and useful control and leveling structure for a silo unloader.

Still a further object of this invention is to provide new and useful means for. controlling the engagement of the ensilage engaging means of a silo unloader with the ensilage.

Yet another object of this invention is to provide unique wall engaging wheel structure at the outboard end of an elongated conveyor for a silo unloader.

A still further object of this invention is to provide new and useful adjustable drive and supporting structure for a silo unloader including new and useful driving and supporting members.

Still a further object of this invention is to provide new and useful drive mechanism for driving a plurality of members at different speeds.

Other and further objects of the invention reside in the structural features of the supporting, control and drive structure, including specifically the structural features of the wall engaging wheel means, the mechanical leveling means, the supporting means and a differential drive means, and the cooperation thereof.

Still other and further objects of the invention are those inherent and apparent in the structure described, pictured and claimed.

To the accomplishment of the foregoing and related ends, this invention then comprises the features hereinafter fully described and particularly pointed out in the 3,223,25fi Patented Dec. 14, I965 claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

In the drawings, FIGURE 1 is a plan view partly in section, of a silo unloader embodying the structure of the instant invention shown in position on the surface of ensilage within a tower silo, the silo being shown in fragmentary section;

FIGURE 2 is a partially sectional and partially elevational view taken along the line and in the direction of the arrows 22 of FIGURE 1;

FIGURE 3 is a vertical sectional view taken along the line and in the direction of the arrows 33 of FIGURE 1;

FIGURE 4 is an enlarged fragmentary plan view of the outboard end of the unloader illustrating the mechanical control means;

FIGURE 5 is a view taken along the line and in the direction of the arrows S-5 of FIGURE 4;

FIGURE 6 is a view taken along the line and in the direction of the arrows 6-6 of FIGURE 4;

FIGURE 7 is a horizontal sectional view taken along the line and in the direction of the arrows 77 of FIGURE 5;

FIGURE 8 is an enlarged fragmentary horizontal sectional view taken along the line and in the direction of the arrows 8-8 of FIGURE 3;

FIGURE 9 is a horizontal sectional view taken along the line and in the direction of the arrows 9-9 of FIG- URE 8;

FIGURE 10 is a vertical sectional view taken along the line and in the direction of the arrows 101t'i of FIG- URE 8;

FIGURE 11 is a view similar to FIGURE 4 but showing means for adjusting the horizontal position of the ensilage engaging wheel of the leveling and control means;

FIGURE 12 is an elevational view taken along the line and in the direction of the arrows 1212 of FIGURE 11 and showing means for adjusting the vertical position of the wall engaging wheel of the control means;

FIGURE 13 is a schematic top plan view of a modified form of the invention showing in exaggerated form alternate positions for the outrigger driving supporting hubs; and

FIGURE 14 is a fragmentary elevational view, similar to FIGURE 3 but showing the means for adjusting the vertical and horizontal positions of the outrigger driving and supporting hubs, which forms the modification of FIGURES 13 and 14.

The structure of this invention will be explained with reference to its use in position upon an ensilage mass within a tower or upright silo. As shown, the silo Wall is of right circular cylindrical section. However, it is to be understood that walls of other than right circular cylindrical section may be used, if desirable or necessary, such as outof-round Walls, polygonal walls, rectangular walls, etc. so long as a substantially unobstructed course or ambit is grgvided for the wall engaging wheels of the unloader.

-The term silo thus contemplates, whether the silo wall extends above or below the ground, a bin or tank or similar structure from which ensilage is to be unloaded. In addition to the unloading of ensilage, or preserved fodder, the present invention is extremely useful for the unloading of other dry or semi-dry, amorphous or crystalline materials in fragmentary form, or which may be reduced to fragmentary form. Thus, the invention is also extremely useful for unloading wood chips, walnut or other shells, pellets and particles of various kinds, etc.

The invention will be explained principally with reference to unloading of ensilage, but without limitation of the foregoing.

Reference is now made to the drawings, and particularly to FIGURE 1. In the drawings, the silo unloader generally designated 10, is shown in position within the confine of the circular silo wall 11 and positioned with reference to the silo wall by three wall engaging Wheels 12, 13 and 14. For convenience, wheel 12 is termed the advance wheel, wheel 13 the leading wall wheel and wheel 14 the trailing wall wheel. A fourth wheel, control wheel 15, is also normally in communication with the wall of the silo. The Wheels 12-15 ride over the surface of the silo wall in a horizontal direction as the unloader rotates within the silo in the direction of the arrow 16 of FIGURE 1 during operation.

The structure as shown includes two outrigger driving and 'supporting hubs 20 and 21, providing means which, along with the conveyor iiighting, substantially support the structure. Wheel provides additional support, leveling or control of the position of the unloader and control of the depth of cut as later explained. An elongated conveying structure 22 provides means for engaging the surface of the ensilage and operating upon the material of the mass to loosen it and convey it substantially axially of the silo wall or in the direction of the arrow 23. The ensilage so conveyed is conveyed to a central impeller assembly 24, and the conveying structure 22 is positioned by the wall engaging wheels 13 and 14 and maintained in level (or with its outward end in slightly declined) position by the leveling and control structure comprising the wheels 15 and 25.

The entire structure is driven by a motor 26, shown as electric, and connected to a suitable power supply, operating a belt or chain drive through a gear assembly 27. The conveying structure serves as a gathering or collecting arm means and comprises a pair of parallel augers 28 and 29 of helical fiighting (the fiighting being oppositely dis posed) supported upon central shafts and extending radially of the silo, at the outside or outboard end of each of which is provided a wall cutter or cleaner (30 and 31 respectively, each comprising a toothed member) the augers at their inner end or inboard end being supported by and driven through the gear assembly or gear box 27. A cross plate 32 serves as a frame support for the wall engaging wheels 13 and 14. Outer bearing brackets 33 are secured to and depend therefrom and support outboard bearings for the augers 28 and 29-. The cross plate is welded or otherwise secured to the parallel frame members 34 and 35, in this instance tubular. As shown, it is bolted to angle members 36 which are in turn welded to members 34 and 35.

The augers 28 and 29 are thus supported by having their shafts 28A and 29A journalled for rotation at their outer end in bearings supported by the brackets 33 and at their inner end by bearings supported by the gear box assembly 27.

The frame members 34 and are provided with inwardly extending ends 40, 41 which serve to support the electric motor 26 as subsequently explained. Gear box 27 is provided with a cross member 43 secured thereto by bosses, usually welded, and having turned ends secured to lugs on each of members 34 and 35 (FIGURE 1). Gear box 27 is also joined to a second cross member 44 (FIG- URE 2) also secured to frame members 34 and 35 by lugs. The elevating means or central impeller assembly 24 is provided with a scroll housing 45 of the type shown in Patent 2,794,560, and reference thereto is made for the specific details of the elevating means.

Scroll housing 45 has an open bottom and an open side at 46 for the reception of ensilage. Ensilage is thus gathered from the top of the mass E by the gathering means 22, drawn into the center of the silo and conveyed in the elevating means 24 which impels it upwardly and outwardly through a chute or discharge means and thence through the door of the silo, as specifically explained and shown in co-pending application Serial No. 732,735, now Patent No. 3,017,043. Since it forms no part of this invention per se, it will not be further explained.

The housing 45 is supported by cross braces or members 47 and 48 attached to suitable lugs extending upwardly and welded to members 34 and 35 so as to be supported thereby. The exit 49 of housing 45 i positioned interior of and secured to a contact ring assembly of the type shown in Patent 2,794,560. The ring assembly is in turn provided with a chute assembly and torgue arm means as shown in application Serial No. 732,735, now Patent No. 3,017,043, to which reference is made for this structure. It will not further be explained in detail since it forms no part of the invention per se. Attached to the ring assembly is the cable supporting means, also shown and described in application Serial No. 732,735, now Patent No. 3,017,043, which in this invention is merely used as a means of lifting or lowering the entire structure from or into position, or lifting it at the end of operation to prevent its freezing down to the ensilage. In ordinary unloading operation of the invention, it is not used.

The wall engaging wheel means will now be specifically described and is illustrated best with reference to FIG- URES l, 2, 4, 5, 6 and 7.

The wheels 13 ind 14 are each journalled in a yoke 49 in turn pivoted in a pair of plates 50. Plates 50 are fastened one on either side of a shallow channel member 51. Channel members 51 are pivotally secured by bolts 52 to outer bearing bracket 32. A second bolt is provided in each of channels 51 which cooperates with an arcuate slot 52A in bracket 32 so that channels 51 and their cooperating wheels 13 and 14 may be pivoted about pivot 52 and secured in adjusted or pivoted position by tightening the bolts in slots 52A. Thus, the wheels 13 and 14 (as will be seen in FIGURE 7) may be adjusted inwardly and outwardly of the unlo ader (leftwardly and rightwardly with reference to FIGURE 7) by the pivoting of channel members 51 about pivots 52 and then fastening in that adjusted position.

The member 32 is a casting of the plan configuration shown, is provided with lobate portions accommodating the arcuate slots 52A and is offset inwardly as shown in FIGURE 7 so that the wall cutter 31 is inwardly offset with reference to wall cutter 32 Similarly the wheel 13 is inwardly offset with reference to wheel 14.

The wheel 12 is positioned immediately adjacent the hub 20 and secured to the members 34 by a brace 38 and by a second angle brace 39 as shown in co-pending application Serial No. 732,735, now Patent No. 3,017,043. It is thus positioned slightly forward of an immediate adjacent the hub 20.

The control or leveling structure comprising the control wheel 15 and ensilage wheel 25 will now be specifically explained.

Ensilage wheel 25 (FIGURES 4, 5 and 6) is pivoted on an axle joined to a vertically extending rod 54 received in a sleeve 55 and adjustably secured by a set-screw 56. Thus, the rod 54, when screw 56 is loosened, may be moved upwardly and downwardly with reference to FIG- URE 5 and secured in such adjusted position by tightening screw 56. Sleeve 55 is supported by a tubular member 57 having a first horizontal portion 58 extending at an angle (as seen in FIGURE 4) with reference to a second horizontal portion 59 The member 57 is provided with an upright or vertical portion 60 joined to the horizontal portion 59 and has a flattened end secured to a sleeve 61. Portion 59 is pivotally secured in brackets 62 welded to frame members 34 and 35. Brackets 62 each comp-rises a U-member receiving the tubular member 59 and a plate member securing it therein and bolted to the U-member as seen best in FIGURE 2.

Sleeve 61 receives a rod 63 having an end threaded at its interior for receiving a threaded end of crank 64. Crank 64 is rotatably positioned in. but ax ally immovable with respect to sleeve 61 so that by operation or rotation its threaded end will draw the rod 63 inwardly or outwardly (rightwardly or leftwardly with reference to FIG- URE 4). To the extending end of rod 63 is secured yoke 65 at an angle thereto in which the wheel is journalled for rotation.

Thus it will be seen that engagement of wheel 15 with the wall of the silo will determine the position of wheel through the tubular member 57. As wheel 15 is forced inwardly (rightwardly with reference to FIT- URE 4) wheel 25 will be forced downwardly into engagement with the surface of the ensilage as the portion 59 pivots in brackets 52 (see FIGURE 2) and the outboard end of the silo will be raised. This condition will occur when the outboard end of the silo unloader has dropped, for the silo unloader will pivot in a vertical plane about its inboard end and wheel 15 will be forced inwardly by such pivoting. If the outboard end of the silo should become unduly elevated, wheel 15 will be permitted to move outwardly (leftwardly with reference to FIGURE 4) and the wh el 25 will be permitted to elevate, thus removing the support that it offers to the outboard end of the unloader and the outboard end of the unloader will engage the ensilage with greater pressure and thus depress to normal position as it chews its way through the ensilage. The supporting hubs are positioned, and the unloader constructed to provide a substantial excess of weight on the outboard end of the unloader over the inboard end to insure dropping of that end when support is removed from wheel 25. Additionally, the unloader preferably operates with its outboard end slightly declined so that the surface of the mass from which ensilage is removed retains the shape of a slight cone during operation. (See FIGURE 3. This has been omitted from FIGURE 1 for the sake of clarity.)

As will be seen, manipulation of handle 64 will permit the inward or outward adjustment of wheel 15 to determine desired operating position in the event manual adjustment is desired. Likewise, the wheel 25 may be manually vertically adjusted, which adjustment will determine the depth of cut of the unloader.

The silo unloader is not suspended during operation but is supported substantially by the two augers 23 and 29 and the two driving hubs 20 and 21. In addition, wheel 25, if the outboard end of the unloader has dropped, will provide material support therefor but will provide very little or only control support when the angers are level or in previously adjusted declined position and the unloader is in normal operating condition as previously explained. The silo unloader therefor is thus designed to rest in the main upon the angers and the outrigger hubs 20 and 21. Hub 2% is positioned ahead of the silo unloader as it rotates over the surface of the ensilage, has a smooth exterior surface and includes a hollow outer shell 70, open at both ends and a central annular depression 71. To the interior of the central depression 71 is secured two bulged partitions 72, joined to an axle '73 for rotation therewith and to be driven thereby. Axle 73 is journalled in a sleeve bearing 74 and connected to a universal 75 provided at its other end With a square shaft 76 received slidably in a square sleeve 77 in turn connected to a second universal 73. Driving universal 72?: is a shaft 795 driven as later described.

Sleeve 74 is supported by a circular plate 89 aiiixed to it by a spacer which is in turn bolted to an identical plate 81. Plate 81 is welded or otherwise secured to a square bar 82 slidably received in a square tube 83. Bar 82. is provided with a plurality of spaced apertures and tube 33 is provided with an aperture in which is positioned a bolt 84, which may be passed through any one of the spaced apertures of bar 82 for adjustment of the hub 20 inwardly and outwardly (leftwardly and rightwardly) with reference to FIGURE 3. Thus, it will be seen that on such adjustment, bar 76 slides in sl eve 77, but still in driving engagement and bar 8?. slides in sleeve 83 without being permitted to turn. A tubular brace 85 is secured at lug 86 to housing 45 and at lug 87 to sleeve 83.

The hub 21 is substantially identical with hub 20 but it is provided with cleat means or a plurality of lugs 90 extending at the center therefrom. Lugs 90 comprise angle members welded or otherwise secured thereto.

The supporting structure for hub 21 is identical with that for hub 20 but extending oppositely and in prolongation of the structure for hub 20. The shaft 79F for hub 21 is driven at a faster speed than the shaft 793 for hub 2t) so that hub 21 is the fast or more rapidly rotated hub as will be later explained.

The members 85 are joined to the same pin on housing 45 which is on a vertical line substantially midway between the two angers 28 and 29. The inner ends of members 83 are secured together and each of members 83 is supported by brackets 91 connected to members 34 and 35, respectively. Each of the members 83 is provided with an angle brace 92 (FIGURE 1) joined at one end to member 83 and to the other end to a lug on members 34- and 35 respectively.

It will be seen in FIGURE 3 that the ensilage engaging portions of hubs 2t) and 21 are on diverging lines declining from the horizontal, thus the bottom portions of the periphery of the hubs 2d and 21 are positioned somewhat below the bottom portions of the periphery of angers 23 and 29, the outer portion of each hub being in greater ensilage engagement than the inner portion. To state this another way, the hubs are not level at the outer edge and the inner edge, and the lower surfaces of the hubs are each positioned at a lower level than the lower surfaces of the angers.

As explained above, the outboard end of the unloader .is preferably slightly declined so that corresponding points in the ensilage engaging portion of each auger are on a line declined from the center of the silo toward the silo wall to form a declined radial line. The hubs are positioned so that the extending supporting arm structure therefore rests on similar declined radial lines but preferably at substantially right angles to the exten sion of the angers, both operating to provide the slight conical surface to the mass from which ensilage is removed.

The motor 26 drives an endless belt or chain 93 which passes around pulley 94 to drive the impeller of the central impeller assembly 24 and at the same time passes around pulley 95 to drive shaft 95 of gear assembly 27. The belt 93 is also passed around an idler pulley 9S journalled in uprights 97 positioned on member 35. It may be adjustably positioned for tightening if so desired.

The motor 26 is supported on a platform 37 in turn supported on four stub sleeves 38 two of which are positioned on member 34 and two of which are positioned on member 35. Set screws 39 serve to hold the motor in position with belt 96 tightened by adjustment leftwardly or rightwardly with reference to FIGURE 2.

Rotation of pulley @5, which is secured to shaft 96 (FXGURE 8), rotates the shaft 96 in bcarin s 99 and ran in gear box or casing 101 and rotates a lefthand worm 1'92 and a righthand worm Hi3 joined for rotation thereto.

Shaft 96 when viewed from FIGURE 10 is rotating in a clockwise direction. The worm ltlZ pinned thereto likewise rotates in a clockwise direction and engages a gear lil l secured to the end of shaft 29A of auger 29 to rotate that shaft from right to left (FIGURE 8). Worm 103 is also pinned to shaft 96 and by rotation of shaft 96 engages gear 108 and through it rotating shaft 23A from left to right when viewed in FIGURE 8. The augers are thus contrarotating.

Gear 1&4 is pinned to shaft 29A which is journalled in bearings 106 and 107 in housing 101. Also pinned to shaft 29A is a righthand worm which engages gear 109 on shaft 798 for hub 20. i

Worm 103 engages a cooperating gear 108 on shaft 28A which through the lefthand worm 111 secured thereon drives a cooperating gear 115 pinned to shaft 79F for fast drive hub 21. Shaft 759E is journalled for rotation in bearing bosses 115 and 116 of housing 1111 and retained in position by collars 117 secured thereto. Shaft 798 is journalled in bearing bosses 113 and 114 and is retained by identical collars 117. Worm 102 thus rotates worm gear 104 which is journalled in bearings 1116 and 157 and worm 103 rotates gear 108. Gear 1118 .is pinned to shaft 28A which is journalled in bearings 1116A and 157A.

Gears 104 and 1025 are identical as are Worms 102 and 1113 but oppositely directed. Worms 154 and 111 in addition to being oppositely directed are preferably of differing sizes. Thus, as will be seen in FIGURE 9 worm 1115 is smaller than worm 111 and corresponding gear 1199 is larger than corresponding gear 110. This insures that shaft 79E of hub 21 will be rotated at a faster speed than shaft 795 of hub 20 and consequently provides a differential drive for the two hubs 20 and 21. Less preferred, the worms 105 and 111 may be made the same size and differential drive accomplished by moving hub 20 closer to the center of the machine than hub 21.

The bearings 99 and 100 as well as bearings 11% and 107, and 106A and 107A are of any suitable type, as shown providing end caps or retainers and tapered roller bearings to absorb thrust in addition to avoiding friction of revolution.

The bearings for shafts 75F and 79S comprise merely machined surfaces in the housing 101 in which the shafts are journalled, bearing sleeves being provided if desired. The collars 117 like gears 109 and 114), are pinned to the shafts 79S and 79F and thus serve to retain the shafts in position. The housing 101 is of the configuration shown and provides a fluid tight closure in which lubricating oil is poured to provide a continuous oil bath for the gears. It is provided with a removable cover 101A bolted thereto through a gasket, not shown, by bolts, not shown.

In operation the unloader will rest on the surface of the ensilage and the hubs 20 and 21 may be adjusted inwardly and outwardly to be positioned adjacent the silo wall. It has been found extremely important that they be positioned from the silo wall a distance equal to to of the diameter of the silo. Hub 21 will rotate at a faster speed than hub 20 insuring the constant engagement of wheels 13 and 14 with the silo wall. Wheels 13 and 14 will pivot about a horizontal axis to allow the shifting of the outboard end of the unloader upwardly or downwardly smoothly as it passes over irregularities in the ensilage. At the same time the operation of the leveling assembly comprising wheels 15 and 25, by engagement with wheel 15 with the silo wall 11 will provide none, a little, or more support for the outboard end of the unloader to keep it level, or in predetermined declined position. The wheels 13 and 14 may be adjusted inwardly or outwardly to provide proper engagement with the silo wall and the wheels 15 and 25 may be also adjusted.

In FIGURES 11 and 12, there is shown a modified form of the leveling structure in which member 57 is replaced by a member 57A.

Member 57 has its portion 58 severed to provide the end 58A and a portion 58B secured to sleeve 55. The two portions are connected by stub connector 58C pinned to portion 58B and slidable in portion 58A. Portion 58A is provided with a guide slot 58D which receives a pin secured to connector 58C for preventing rotation thereof in end 58A but permitting axial adjustment therein. The set screw 58E may be loosened or tightened to provide such adjustment. Thus, in the modification shown in FIGURES 11 and 12, the wheel 25 may also be adjusted horizontally as well as vertically.

In this modification, as shown in FIGURE 12, portion 60 has been likewise severed to provide end 60A and a portion 608, portion 60B being attached to sleeve 61 and pinned to a stub connector 6110. Portion 60A is provided u with a guide slot 60D in which a pin joined to shaft 60C reciprocates. A set screw 66E may be loosened and tightened to provide vertical adjustment for sleeve 61 and consequently of wheel 15.

In FIGURE 13, there is shown a schematic View, the positions to which the hubs 24) and 21 may be adjusted. The positions are exaggerated for illustration. Thus, in the structure of the modification of FIGURES 13 and 14, hub 21 may be moved forwardly to position A or rearwardly to position B and hub 20 may be moved forwardly to position C or rearwardly to position D. Normally hubs 2t and 21 would be moved either forwardly or rearwardly in unison to shift the location of the fulcrum of the structure and consequently the weight on the outboard end, as desired, but in some instances it might be desirable to shift one forwardly and one rearwardly such as to positions A and B or C and D because of driving conditions in particular ensilage.

The structure shown in FIGURE 14 permits such adjustment. In this modification, members 83A are substituted for members 83, are shorter and pivoted about a vertical axis or pivot 83B, in turn pivoted about the horizontal axis or pivot 33C. A stiffening member 83D extends between frame members 34 and 35 for additional support and receipt of thrust.

Members 85 have each been replaced by member 85A receiving therein a rod member 858, member 85A being provided with a plurality of apertures for the reception of a pin passed through it and member 8513. Member 858 is provided with a socket at 85C engaging a ball 85D secured by bracket 85E to a plate 85F in turn secured to the housing 45.

Thus, it will be seen that adjustment of members 85A and 8513 will allow the arms 83A to be pivoted about 830 in a vertical direction. Likewise, the arms 83A may be pivoted in a horizontal direction about pivot 8313, members 858 pivoting on the ball and socket joint SSC-D.

In the modification of FIGURES l3 and 14, as will be appreciated, the braces or tiebars 92 have substituted therefor braces providing connections permitting adjustment of the hub forwardly or backwardly in a horizontal direction. Thus, as shown in FIGURE 13, members 92 have been replaced by sleeves 92A cooperating with rods 9213 (joined by pin and aperture connections similar to the joining of members 85A and 8513), members 92A being pivoted about a vertical axis to member 83A at 92C, members 92B being pivoted about a vertical axis at 92D to frame members 34 and 35.

In the modifications of FIGURES l3 and 14, it will be noted that the tiebars 92A-B are connected to the members 34 and 35 adjacent the outboard end of the unloader which manner of connecting has been found to have advantages.

It will thus be seen that there is provided a silo unloader having new and useful supporting and driving structure providing a diiferential drive and in which the unloader is supported substantially entirely on the auger fiighting and the outrigger drive hubs. The silo unloader 1s provided with a mechanical self leveling structure of unique and facile construction. The unloader is driven through a gear assembly providing differential drive of simple construction and reliable performance. The drive hubs are positioned as Outriggers and telescopically joined for adjustable extension.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specific embodiments described are given by way of example only and the invention is limited only by the terms of the appended claims.

What is claimed is:

1. A silo unloader including a plurality of augers positioned in parallel providing an inboard end and an outboard end, wall engaging wheel means for positioning the outboard end thereof with respect to a silo wall, a pair of drive hubs positioned one on either side of said inboard end and providing outrigger drive means for said silo unloader, one of said drive hubs being provided with a plurality of cleat means for engaging the surface of the ensilage, a well engaging wheel positioned adjacent one of said hubs for engaging the wall of the silo, ex-

tending shaft means between each of said hubs and said unloader, and extending supporting members between each of said hubs and said unloader, and means whereby each of said hubs may be extended or retracted with reference to said unloader.

2. The structure of claim 1 characterized in which a single motor drives both of said hubs through a differential gearing and drives said augers.

3. A silo unloader including an elongated ensilage engaging and conveying means supported on the surface of the ensilage within a silo, outrigger driving hubs positioned in prolongation and substantially at right angles to the extension of said elongated ensilage engaging and conveying means and at the inboard end thereof, said silo unloader having an excess of weight at said outboard end and control means engaging the ensilage thereat for determining the vertical position of said outboard end.

4. The structure of claim 3 in which control means is provided adjacent said outboard end for determining the engagement thereof with said ensilage.

5. In a silo unloader having an outboard end positioned adjacent the wall of the silo, a positioning means for the outboard end thereof comprising an ensilage engaging wheel means positioned in a direction trailing the rotation of the silo unloader, and a wall engaging wheel means positioned against the wall of the silo unloader, both said wheel means being joined to the ends of a common support, and said common support being pivoted to said outboard end for rotation.

6. The structure of claim 5 in which means is provided for adjusting the position of said wall engaging wheel inwardly and outwardly of the unloader.

'7, A silo unloader including a frame providing an outboard end adjacent the wall of the silo, wall engaging Wheel means for determining the position of said outboard end, an additional wall engaging wheel positioned above said wall engaging means and adjustably secured to a vertical member, said vertical member joined to a horizontal member and said horizontal member being joined to a wheel supporting means, said horizontal member being journalled for rotation about a horizontal axis, and a wheel joined to said wheel supporting means and adjustably secured thereto.

8. In a driving mechanism for a silo unloader, a first shaft driven by a motor, said shaft containing a pair of oppositely directed worms of the same diameter, said worms each engaging a gear secured to a shaft, and a helical conveyor secured to each of said last shafts, a Worm secured to said each of said last shafts, said worms being of opposite direction, and the diameter of one of said worms being larger than the diameter of the other of said Worms, a fourth shaft connected to a drive hub and provided with a gear for engaging the worm of larger diameter and a fifth shaft similar thereto but oppositely directed and provided with a gear of smaller diameter for engaging the worm of larger diameter, and drive means secured to said fourth and fifth shafts.

9. A silo unloader having an inboard end and an outboard end and adapted to rotate over the surface of material being unloaded and about said inboard end, a pair of drive hub means positioned in prolongation, one at either side of said unloader, and positioned at a greater and lesser extension from said unloader and operating at the same rotational speed to provide a differential drive for the unloader.

10. In a silo unloader, in combination: a frame, means rotatably suspending said frame in a silo above the surface of the silage; driven silage cutting and feeding means in said frame including end cutters at an end of the frame to cut silage from the silo wall; guide wheel means on the frame and bearing on the silo wall immediately adjacent said end cutters; a motor on said frame; a leading drive system including a leading outrigger at one side of the frame, a leading thrust rod connected to said outrigger and to the frame adjacent the guide wheel means, and a leading drive wheel mounted on the outrigger and operatively connected to the motor; a trailing drive system including a trailing outrigger at the other side of the frame with its free end substantially behind the leading drive wheel, a trailing thrust rod connected to said trailing outrigger and to the frame adjacent the guide wheel, and a trailing drive wheel mounted at the free end of the trailing outrigger and operatively connected to the motor, said leading and trailing drive systems being constructed, arranged and coordinated to provide a predetermined driving force at the periphery of the leading drive wheel and a predetermined greater driving force at the periphery of the trailing drive wheel, whereby under usual operating conditions both thrust rods are in compression and the trailing drive wheel thrusts said guide wheel means against the silo wall to maintain a proper cutting relationship between the end cutters and the silo wall as the frame rotates, while upon encountering means abnormally resisting the usual rotation of the frame produced by said trailing wheel thrust the leading drive wheel ,places the leading thrust rod under tension and pulls the guide wheel means around the silo wall until usual operating conditions are restored.

11. A silo unloader having silo wall engaging guide wheels, a plurality of material engaging drive means secured to said silo unloader, and power means secured to said silo unloader and said drive means, said power means including power transmitting means for driving said drive means at differential speeds; whereby at least one; of said guide wheels is biased to contact with a silo wa l.

12. A rotating silo unloader having a plurality of material engaging drive means, one of said drive means being positioned at greater extension from the unloader than another of said drive means, and means secured to said silo unloader and said drive means for driving all of said drive means at the same rotational speed; whereby said one drive means describes a larger circle than said another drive means to provide a differential drive for said silo unloader.

13. In a silo unloader, in combination: a frame, driven silage cutting and feeding means in said frame including end cutters at an end of the frame to cut silage from the silo Wall; guide wheel means on the frame and bearing on the silo wall immediately adjacent said end cutters; a motor on said frame; a leading drive system including a leading outrigger at one side of the frame, a leading thrust rod connected to said outrigger and to the frame adjacent the guide wheel means, and a leading drive wheel mounted on the outrigger and operatively connected to the motor; a trailing drive system including a trailing outrigger at the other side of the frame with its free end substantially 180 behind the leading drive wheel, a trailing thrust rod connected to said trailing outrig er and to the frame adjacent the guide wheel, and a trailing drive wheel mounted at the free end of the trailing outrigger and operatively connected to the motor, said leading and trailing drive systems being constructed, arranged and coordinated to provide a predetermined driving force at the periphery of the leading drive wheel and a predetermined greater driving force at the periphery of the trailing drive Wheel, whereby under usual operating conditions both thrust rods are in compression and the trailing drive wheel thrusts said guide wheel means against the silo wall to maintain a proper cutting relationship between the end cutters and the silo wall as the frame rotates, while upon encountering means abnormally resisting the usual rotation of the frame produced by said 1 1 trailing wheel thrust the leading drive wheel places the leading thrust rod under tension and pulls the guide wheel means around the silo wall until usual operating conditions are restored.

14-. In a silo unloader having an inboard end and an outboard end and adapted to rotate over the surface of material being unloaded and about said inboard end, the improvement of a pair of drive hubs positioned in prolongation, one at either side of the unloader, said unloader having a conveying means providing a plurality of edge surfaces for engaging the surface of the material being conveyed whereby said silo unloader is substantially supported on said drive hubs and said edge surfaces, means for driving each hub, and adjustable means secured to said silo unloader and to said drive hubs whereby said hubs may be extended or retracted relative to the silo unloader, said adjustable means having means for holding said drive hubs at selected radial positions.

15. A silo unloader having a plurality of material engaging drive means, power means secured to said silo unloader and said drive means for driving said drive means, said power means including differential gearing for driving at least one of said drive means at a difierent speed relative to the other drive means to provide a differential drive for said silo unloader.

16. A- silo unloader having a wall engaging member, a first and second material engaging drive means, power means secured to said silo unloader and said first and second drive means for driving said first and second drive means, said power means including means for establishing a diiference in the relative speeds between the first and the second drive means to provide a differential drive for said silo unloader, the faster turning of said drive means having less power than the other drive means and being positioned and arranged to bias said Wall engaging member into contact with the silo wall and the other drive means positioned and arranged to pull the biased wheel away from said Wall when said wall engaging member hits an obstruction on the silo wall.

References Cited by the Examiner UNITED STATES PATENTS 1,192,832 7/1916 Sherman 198-33.2 1,550,311 8/1925 Foster.

2,521,658 9/1950 Van Voorhis 74-665 2,651,438 9/1953 Peterson.

2,671,696 3/1954 McLean 30256 2,677,474 5/1954 Long.

2,718,969 9/ 1955 Cordis.

2,756,112 7/1956 Knutson 30256 2,801,885 8/1957 Harris.

2,864,655 12/1958 Caron 30256 HUGO O. SCHULZ, Primary Examiner.

ERNEST A. FALLER, Examiner. 

1. A SILO UNLOADER INCLUDING A PLURALITY OF AUGERS POSITIONED IN PARALLEL PROVIDING AN INBOARD END AND AN OUTBOARD END, WALL ENGAGING WHEEL MEANS FOR POSITIONING THE OUTBOARD END THEREOF WITH RESPECT TO A SILO WALL, A PAIR OF DRIVE HUBS POSITIONED ONE ON EITHER SIDE OF SAID INBOARD END AND PROVIDING ONE ON EITHER SIDE OF SAID SILO UNLOADER, ONE OF SAID DRIVE HUBS BEING PROVIDED WITH A PLURALITY OF CLEAT MEANS FOR ENGAGING THE SURFACE OF THE ENSILAGE, A WELL ENGAGING WHEEL POSITIONED ADJACENT ONE OF SAID HUBS FOR ENGAGING THE WALL OF THE SILO, EXTENDING SHAFT MEANS BETWEEN EACH OF SAID HUBS AND SAID UNLOADER, AND EXTENDING SUPPORTING MEMBERS BETWEEN 